Natural fiber coated artificial turf infill

ABSTRACT

The method includes providing a base composition including a natural fiber, at least one first type of pigment, and a fluid binding agent. The fluid binding agent includes at least one type of polymer component. The natural fiber includes any one of hemp fiber, burlap fiber, sisal fiber, elephant grass, cotton, coconut fiber, and combinations thereof. The method further includes mixing the base composition. The method further includes adding water and a catalyst to the base composition during the mixing of the base composition to cure the fluid binding agent and the at least one first type of pigment into a base coating of the natural fiber.

FIELD OF THE INVENTION

The invention relates to artificial turf and methods for the manufacture of artificial turf infill.

BACKGROUND AND RELATED ART

Artificial turf or artificial grass is surface that is made up of fibers which is used to replace grass. The structure of the artificial turf is designed such that the artificial turf has an appearance which resembles grass. Typically artificial turf is used as a surface for sports such as soccer, American football, rugby, tennis, golf, for playing fields, or exercise fields. Furthermore artificial turf is frequently used for landscaping applications.

Artificial turf may be manufactured using techniques for manufacturing carpets. For example artificial turf fibers which have the appearance of grass blades may be tufted or attached to a backing. Often times artificial turf infill is placed between the artificial turf fibers. Artificial turf infill is a granular material that covers the bottom portion of the artificial turf fibers. The use of artificial turf infill may have a number of advantages. For example, artificial turf infill may help the artificial turf fibers stand up straight. Artificial turf infill may also absorb impact from walking or running and provide an experience similar to being on real turf. The artificial turf infill may also help to keep the artificial turf carpet flat and in place by weighting it down.

European Patent EP 2 206 833 A1 discloses a method for producing a particulate infill material for synthetic-grass structures envisages providing a mass of thermoplastic material with a filler consisting of coconut-based material and subjecting said mass of thermoplastic material with the filler consisting of coconut-based material to granulation so as to obtain the aforesaid particulate infill material. Preferentially, the thermoplastic material is in particulate form, and the coconut-based material is in particulate form (fibrous, ground and/or shredded). The mixture obtained by mixing the thermoplastic material and the coconut-based material is preferentially heated in order to bring about softening of the thermoplastic material with the corresponding formation of a matrix of thermoplastic material that incorporates the coconut-based material as filler.

SUMMARY

The invention provides for a method of manufacturing artificial turf infill, a method of manufacturing artificial turf, and artificial turf in the independent claims. Embodiments are given in the dependent claims.

In one aspect the invention provides for a method of manufacturing artificial turf infill. The method comprises first providing a base composition comprising a natural fiber, a at least one first type of of pigment, and a fluid binding agent. The fluid binding agent comprises at least one type of polymer component. The natural fiber comprises any one of the following: hemp fiber, burlap fiber, sisal fiber, elephant grass, cotton, coconut fiber, and combinations thereof.

The at least one first type of of pigment may be an individual pigment or it may also be a combination or mixture of different pigments. For example, the at least one first type of pigment may be a green pigmentation used for coloring artificial turf infill that is a mixture of green, white, yellow, and black pigments.

In the next step the method further comprises mixing the base composition. The method further comprises adding water and a catalyst to the base composition during the mixing of the base composition to cure the fluid binding agent and the at least one first type of of pigment into a base coating of the natural fiber. The term “base” in base coating is intended as a label to identify the coating of the natural fiber. The term “base” as used herein is therefore not intended to have a specific meaning outside of its use as a label in the context of the coating of the natural fiber. Hence, a “base coating” as understood herein is a coating that may or may not form a base for one or more additional coatings.

This embodiment may be beneficial for a variety of reasons. In one aspect the method may be beneficial because it may provide for a means of partially coating the natural fiber. The natural fibers are able to absorb and desorb water. It may be beneficial before a sporting event or game to spray water onto the artificial turf infill for it to absorb water. As the sunlight or hot air heats the artificial turf infill it may then desorb or evaporate water keeping the surface of an artificial turf cool. The amount of time that the artificial turf infill is able to retain water may be controlled by only partially covering the artificial turf infill.

A further advantage may be that the base coating provides protection for the natural fiber and helps it hold together. This may provide for an artificial turf infill which lasts for a longer period. Another advantage may be that the pigment provides a more natural color for the artificial turf infill. For example a brown or a green color may be used. If the natural fibers are brown colored the inclusion of a green pigment may be beneficial in that the artificial turf infill has both brown and green color and therefore makes the resulting artificial turf look more realistic or lifelike.

Another advantage may be that the fluid binding agent may partially absorb into the natural fiber and provide for a very strong bond between the natural fiber and the base coating. The use of a fluid binding agent comprising at least one polymer component may be beneficial because it may provide for a flexible artificial turf infill which has lifelike and/or also shock absorbing properties which help to protect people or players using an artificial turf manufactured with an artificial turf infill.

The use of natural fibers, and hemp in particular, may additionally be advantageous over coconut fibers as hemp and other natural fibers may be less flammable. In some cases the hamp and other natural fiber may also absorb water better than coconut fibers do. The absorption of water by the natural fiber may be advantageous because the artificial turf can be sprayed with water before a game. The evaporation of water from the natural fibers may have a natural cooling effect and may help reduce the temperature of the artificial turf during a game which is played in sunlight.

The use of hemp may also be beneficial because hemp is naturally resistant to fungi in comparison with coconut fibers. Hemp also has the benefit of being very skin friendly. Hemp is less abrasive and/or prickly than many other natural fibers such as wood chips or coconut fibers.

The use of natural fibers, and hemp in particular, as an infill material may also be beneficial because it has superior damping and shock absorption properties. A player who falls on an artificial turf with an infill according to an embodiment may in some cases be less likely to be hurt than if the player fell on an artificial turf that had a predominantly coconut fiber based infill.

The use of natural fibers may also be beneficial because they have low thermal conductivities in comparison to, for example, rubber granulate. This may help to reduce how hot an artificial turf surface is when exposed to sunlight.

The method of manufacturing artificial turf infill may be part of a method for manufacturing artificial turf.

In another embodiment the natural fiber consists of any one of the following: hemp fiber, burlap fiber, sisal fiber, elephant grass, cotton, coconut fiber, and combinations thereof.

In another embodiment the natural fiber consists of any one of the following: hemp fiber, burlap fiber, and sisal fiber, and combinations thereof. The use of the hemp fiber, burlap fiber, and sisal fiber over other types of natural fibers may be beneficial because these fibers provide superior water absorption properties as well as an increased resistance to decay due to funguses.

In another embodiment, the method further comprises providing a subsequent composition comprising the natural fiber with the base coating, the at least one second type of pigment and the fluid binding agent. The method further comprises mixing the subsequent composition. The method further comprises adding water and the catalyst to the subsequent composition during the mixing of the subsequent composition to cure the fluid binding agent and the at least one second type of pigment into a subsequent coating of the natural fiber.

The at least one second type of pigment and the at least one first type of pigment may be identical or they may be different. If they are the same then the coating of the natural fiber will be of a uniform color. If the at least one second type of pigment and the at least one first type of pigments are different colors then the two colors can be chosen so that the resulting artificial turf infill has a more natural and earth like appearance.

The method further comprises providing the natural fiber with the subsequent coating as artificial turf infill.

The coating of the natural fiber in at least two steps as described above, may be beneficial because it may provide for better coating of the natural fiber For example, during the mixing of the base composition individual fibers of the natural fiber will touch and interact with each other as the base coating on each of the fibers forms. The physical contact between different natural fibers will however cause defects. By coating the natural fiber particles a second time with the subsequent coating, much higher coverage of the natural fiber can be achieved.

As an example, during the formation of the base coating or the subsequent coating the coverage is each only 90% of the surface of the natural fiber. After the base coating has been deposited, roughly 10% of each granule of the natural fiber would be uncoated. There would be small surface defects. Deposition of the subsequent coating would then also cover 90% of the surface. As the interaction between the fibers or particles of the natural fiber is essentially a random process, one can expect that 90% of the defects that were exposed after the deposition of the base coating are coated in this case. The result of doing two coatings is then an artificial turf infill that is 99% coated with only minor amounts of defects, where the natural fiber is not coated with either the base coating or the subsequent coating. This effect may be used to control how quickly water can evaporate from the natural fiber, and thus control how long the cooling effect of this evaporation will be active.

Improving the coverage of the natural fiber may be beneficial in several different situations. For example, it may be desirable to color the artificial turf infill the same or a similar color as fibers or tufts, which are used to manufacture an artificial turf carpet. This may provide a more realistic-looking play surface or playfield. Another advantage is that the elastomeric natural fiber may be better coated and may therefore have superior wear qualities or may even be better isolated from the environment.

In another embodiment the natural fiber comprises fibers with a length less than 5 mm long.

In another embodiment the natural fiber comprises fibers with a length less than 1.5 mm long.

In another embodiment the natural fiber comprises fibers with a length less than 2.5 mm long.

In another embodiment the curing of the base coating and the curing of the subsequent coating is a polymerization process. Within the claims, the term ‘cure’ or ‘curing’ may be replaced with polymerization.

In another embodiment the subsequent coating at least partially covers the base coating.

In another embodiment the base coating only partially covers the natural fiber.

In another embodiment the subsequent coating only partially covers the base coating.

In another embodiment the natural fiber with the base coating and the subsequent coating is re-coated at least one time by performing the following sequence. The first step in the sequence is provide a subsequent composition by adding at least one additive and the fluid binding agent to the natural fiber that has already been coated with the base coating and the subsequent coating. The next step in the sequence is to mix the subsequent composition. The next step in the sequence is to add water and the catalyst to the subsequent composition during the mixing of the subsequent composition to cure the fluid binding agent and the at least one additive into a further coating. The natural fiber with the further coating is provided then as the artificial turf infill. This embodiment may be beneficial because an additional functional coating or layer may be put on the natural fiber. If the at least one first and/or second type of pigment is used again then the natural fiber may be coated a third or more times to improve the coverage and the coating of the natural fiber. Again, this effect may be used to control how quickly water can evaporate from the natural fiber, and thus control how long the cooling effect of this evaporation will be active.

This embodiment may also be beneficial because it may enable the deposition of so-called functional layers or additives, which may add to the utility or wear or usefulness of the artificial turf infill.

In another embodiment the PU catalyst is partially or completely water soluble and is one of the group: secondary amine, tertiary amine, a metal organic catalyst.

Utilization of these catalysts can facilitate production of coatings having openings that expose the natural fiber. In addition, coatings made using these catalysts can have structural integrity and/or durability, and/or mechanical properties which are compatible with the requirements for artificial turf infill.

Moreover control of a quantity of these catalysts can provide for a control of a number and/or size of the openings. As it is mentioned above and further in the text the openings in their own turn can provide for proper absorption and desorption of water from the surface of the fiber opened to air in the openings. At it is mentioned above the processes of water absorption and desorption of water can facilitate keeping the artificial turf infill and as a consequence the artificial turf cool.

In another embodiment the liquid PU component is based on an NCO terminal polymer which might be a pre-polymer, a polymeric isocyanate, an oligomeric isocyanate, a monomer and a mixture hereof.

In another embodiment the liquid PU component is based on an aromatic diisocyanate of the group toluene diisocyanate and/or 2,2′-Methylene diphenyl diisocyanate and/or 2,4′-Methylene diphenyl diisocyanate and/or 4,4′-Methylene diphenyl diisocyanate.

In another embodiment the liquid PU component is based on an aliphatic diisocyanate of the group hexamethylene diisocyanate, isophorone diisocyanate and 1,4-cyclohexyldiisocyanate.

In preferred embodiment the liquid PU component is based on methylene diphenyl diisocyanate (MDI) isomer mixture.

In another embodiment the hydroxyl component for the production of the PU is out of the group polyether polyol or polyester polyol.

In another embodiment the hydroxyl component is based on a polyetherpolyol of the molecular weight 500 to 10000. In a preferred embodiment the polyetherpolyol has a molecular weight of 1500-6000. In a very preferred embodiment the molecular weight is in the range of 2000-4000.

In another embodiment the at least one additive comprises the at least one first and/or second type of pigment.

In another embodiment the at least one additive further comprises a flame retardant like aluminum trihydrate, magnesium hydroxide turning a by itself burnable or flammable elastomeric material into a flame retardant infill material.

In another embodiment this flame retardant additives creates an intumescent coating and is based on intumescent component comprising ammonium polyphosphate or exfoliated graphite or a mixture hereof.

In another embodiment the at least one additive further comprises zeolite. The addition of zeolite may be beneficial because then the surface of the artificial turf infill may be able to absorb or de-absorb water. For example before a football game, which is scheduled to be held in the sun or in hot conditions, water may be sprayed onto the artificial turf and the zeolite may absorb an amount of water. As the sun or hot air heats the artificial turf infill during the game, the evaporation of water may cool the playing surface for the players and make the use of the artificial turf more pleasant.

In another embodiment the at least one additive further comprises methylcellulose, which may be beneficial in a similar way like zeolite for absorbing and desorbing of water, rendering a cooling effect at hot climatic conditions.

In another embodiment the at least one additive further comprises an antibacterial agent.

In another embodiment the at least one additive further comprises silver. Silver may be beneficial as an antibacterial agent.

In another embodiment the at least one additive further comprises chitosan, showing natural antibacterial properties.

In another embodiment the at least one additive further comprises an IR reflective pigment. The use of the IR reflective pigments as mixed metal oxides may be beneficial because it may reflect infrared light. This may reduce the heating of the artificial turf infill. A specific advantage may be that in this case the comparably expensive and precious pigments are merely on the surface of the infill natural fibers.

In another embodiment the at least one first and/or second type of pigment comprises an inorganic pigment, an organic pigment or mixtures thereof.

In another embodiment the at least one first and/or second type of pigment comprises any one of the following: iron oxide, iron oxide hydroxide, chromium(III) oxide, a copper Phthalocyanine pigment, a nickel azopigment, titanium oxide and combinations thereof.

In another embodiment the at least one type of additive is hindered amine light stabilizer (HALS) which is able to protect the PU coating as well as the elastic and/or compression resilient natural fiber against UV degradation.

In another embodiment the at least one type of additive is a thermostabilizing agent, protecting the elastic and/or compression resilient natural fiber against thermal degradation.

In another embodiment the at least one type of additive is an anti-freeze/deicing additive of the group: sodium chloride, potassium chloride, calcium chloride, sodium formate, potassium formate or a mixture hereof. The additive is migrating into the neighborhood of the natural fiber and by this inhibits the formation of ice by freezing humidity between the infill natural fiber particles.

In another embodiment the fluid binding agent further comprises any one of the following: a surfactant, a polyurethane aliphatic isocyanate, a polyurethane aromatic isocyanate, zeolite, an antibacterial agent, silver, IR reflective pigment, and combinations thereof.

In another embodiment the polymer component comprises any one of the following: at least one type of monomer, at least one type of partially polymerized polymer, and combinations thereof.

In another embodiment the polymer component is cured into at least one type of polyurethane by the water and the catalyst.

For example the polymer component could be methylene diphenyl diisocyanate. The polymer component could also comprise polyols.

In another embodiment the catalyst comprises any one of the following: an amine catalyst and a metal organic catalyst.

In another embodiment the method further comprises drying the subsequent composition before providing the natural fiber as the artificial turf infill.

It may also be possible to dry the base composition after coating the natural fiber with the base coating; however, it is not necessary. The water, which is leftover from the formation of the base coating on the elastic and/or compression resilient natural fiber may be used in the reaction of the subsequent composition.

In another embodiment the method is at least partially performed in a flow reactor. In the flow reactor the natural fiber is slowly moved along a linear sequential path, where the natural fibers are generally mixed and moved along. The benefit of using a flow reactor is that the artificial turf infill may be produced on a continuous basis.

In another embodiment the method is at least partially performed as a batch process. The base coating is formed on the natural fiber during an initial or base batch and the subsequent coating is formed on the natural fiber during a subsequent batch. Forming the base coating and the subsequent coating in separate batches may be beneficial because it may enable precise control over the formation of the base and subsequent coatings.

In another aspect the invention provides for a method of manufacturing artificial turf. The method comprises installing an artificial turf carpet. The artificial turf carpet comprises multiple artificial turf fiber tufts. For example, the artificial turf carpet may be a tufted artificial turf carpet. There may be a backing which has tufts of artificial grass fibers tufted into it. The method further comprises providing the artificial turf by spreading a layer of artificial turf infill between the multiple artificial turf fiber tufts. The artificial turf infill comprises a natural fiber. The natural fiber comprises at least two outer coatings. Each of the two outer coatings comprises at least one first and/or second type of pigment and a binding agent. The binding agent comprises at least one type of polyurethane polymer. This method may be beneficial because the artificial turf infill may be more completely covered with the two outer coatings. This may for instance provide superior optical appearance of the artificial turf infill. It may also provide better wear and longevity of the artificial turf infill.

In another aspect the invention provides for artificial turf infill. The artificial turf comprises natural fiber. The natural fiber comprises any one of the following: hemp fiber, burlap fiber, sisal fiber, and combinations thereof. The natural fiber comprises at least one outer coating. The at least one outer coating comprises at least one first type of pigment and a binding agent. The binding agent comprises at least one type of polyurethane polymer. The at least one outer coating comprises openings that expose the natural fiber.

Utilization of the binging agent comprising at least one type of the polyurethane polymer can be advantageous because it can provide the coating with openings which has structural integrity and/or durability, and/or mechanical properties which are compatible with the requirements for artificial turf infill. Moreover the openings can provide for the cooling effect of the artificial turf infill mentioned above and further in the text.

In another embodiment the natural fiber consists of any one of the following: hemp fiber, burlap fiber, sisal fiber, and combinations thereof.

In another aspect the invention provides for an artificial turf. The artificial turf comprises an artificial turf carpet. The artificial turf carpet comprises multiple artificial turf fiber tufts. The artificial turf further comprises the artificial turf infill according to an embodiment. The artificial turf infill is distributed between the artificial turf fiber tufts.

In another embodiment the artificial turf further comprises a sprinkler system. The use of a sprinkler system with the artificial turf may be beneficial because it may be used to automatically wet the artificial turf infill. For example this may be a convenient means of watering the artificial turf during a half time so that the artificial turf can be kept cooler during game play.

It is understood that one or more of the aforementioned embodiments of the invention may be combined as long as the combined embodiments are not mutually exclusive.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following embodiments of the invention are explained in greater detail, by way of example only, making reference to the drawings in which:

FIG. 1 illustrates an example of an artificial turf carpet;

FIG. 2 illustrates an example of artificial turf;

FIG. 3 shows a flow chart which illustrates a method of manufacturing artificial turf;

FIG. 4 illustrates an example of an artificial turf which incorporates a sprinkler system;

FIG. 5 illustrates an example of an artificial turf infill;

FIG. 6 illustrates a further example of an artificial turf infill;

FIG. 7 illustrates a further example of an artificial turf infill;

FIG. 8 shows a flow chart which illustrates a further method of manufacturing artificial turf infill;

FIG. 9 shows a flow chart which illustrates a further method of manufacturing artificial turf infill;

FIG. 10 shows a flow chart which illustrates a further method of manufacturing artificial turf infill;

FIG. 11 illustrates an example of a batch reactor; and

FIG. 12 illustrates an example of a flow reactor.

DETAILED DESCRIPTION

Like numbered elements in these figures are either equivalent elements or perform the same function. Elements which have been discussed previously will not necessarily be discussed in later figures if the function is equivalent.

FIGS. 1 and 2 illustrate the manufacture of an artificial turf using an artificial turf carpet and artificial turf infill. In FIG. 1 an artificial turf carpet 100 can be seen. The artificial turf carpet 100 comprises a backing 102. The artificial turf carpet 100 shown in FIG. 1 is a tufted artificial turf carpet in this example. The artificial turf carpet is formed by artificial turf fiber tufts 104 that are tufted into the backing 102. The artificial turf fiber tufts 104 are tufted in rows. There is row spacing 106 between adjacent rows of tufts. The artificial turf fiber tufts 104 also extent a distance above the backing 102. The distance that the fibers 104 extend above the backing 102 is the pile height 108. In FIG. 1 it can be seen that the artificial turf carpet 100 has been installed by placing or attaching it to the ground 110 or a floor.

FIG. 2 illustrates an artificial turf 200 manufactured from the artificial turf carpet 100 of FIG. 1. To manufacture the artificial turf 200 a infill 202 made up of natural fibers with at least one outer coating is used. The at least one outer coating comprises at least one type of pigment and a binding agent, wherein the binding agent comprises at least one type of polyurethane polymer. The natural fiber may for example be any one of the following: hemp fiber, burlap fiber, sisal fiber, elephant grass, cotton, coconut fiber, and combinations thereof. FIG. 2 shows the artificial turf carpet 200 after artificial turf infill 202 has been spread out and distributed between the artificial turf fiber tufts 204.

FIG. 3 shows a flowchart which illustrates a method of manufacturing the artificial turf 200 shown in FIG. 2. First in step 300 the artificial turf carpet 100 is installed on a surface. The artificial turf comprises multiple artificial turf fiber tufts. Next in step 302 the artificial turf 200 is provided by spreading a layer of the artificial turf infill 202 between the multiple artificial turf fiber tufts 104. The artificial turf infill comprises natural fiber. The natural fiber comprises any one of the following: hemp fiber, burlap fiber, sisal fiber, elephant grass, cotton, coconut fiber, and combinations thereof. The natural fiber comprises at least one outer coating. The at least one outer coating comprises at least one type of pigment and a binding agent. The binding agent comprises at least one type of polyurethane polymer.

FIG. 4 shows a further example of the artificial turf 200. In this example an automatic sprinkler system 400 has been integrated into the artificial turf 200. The sprinkler 400 is depicted as spraying water 402 on an upper surface of the artificial turf 200. The use of an artificial sprinkler may be beneficial in combination with the infill component that comprises both the rubber natural fiber and the natural fiber. The natural fiber may absorb water which through evaporation can help to keep the surface of the artificial turf 200 cool.

FIG. 5 shows an example of an artificial turf infill 202 manufactured from a natural fiber 500. The view in FIGS. 5, 6 and 7 are cross-sectional views. The natural fiber is shown as being partially coated with an outer coating 502. The outer coating 502 is formed from at least one first type of pigment and a binding agent. The binding agent comprises at least one type of polyurethane polymer. The outer coating 502 may provide coloration which may help the artificial turf infill appear more realistic. The outer coating 502 may also help serve to protect and keep the natural fiber 500 from breaking apart prematurely during use. The openings 504 in the outer coating 502 provide access to the atmosphere for the natural fiber 500. This enables the natural fiber 500 to absorb and desorb water. For example when an artificial turf is wetted with for example the sprinkler shown in FIG. 4 the natural fiber can then absorb water. The amount of openings 504 controls how quickly the artificial turf infill 202 will lose its water and its cooling effect.

FIG. 6 shows a further example of an artificial turf infill 202′. The artificial turf infill 202′ is again shown as a cross-sectional view of the natural fiber 500. In this example an additional subsequent coating 600 has been applied to the natural turf fiber 500. The subsequent coating 600 is shown as covering some of the openings 504 that were present in FIG. 5. As a result a number of openings is reduced by applying the additional subsequent coating. Thus the process of water absorption and desorption through the openings can be tuned to a desired level by applying the subsequent coating. The subsequent coating 600 also partially covers some of the previously coated base coating 502. As a result the structural integrity, and/or durability, and/or mechanical properties of the coating comprising the outer coating 502 and the subsequent coating 600 can be improved or tuned to a desired level. The subsequent coating 600 may comprise a second type of pigment and the binding agent. The binding agent comprises at least one type of polyurethane polymer again. In some instances the first and at least one second type of of pigments are identical. In other cases they may be two different colors. Using two colors that are the same may enable more uniform color coding of the natural fiber 500. Using two different colors may enable a more lifelike appearance for the natural fiber 500. It can be seen that the number of openings 504 has been greatly reduced. This may provide for a means of controlling how exposed the natural fiber 500 is to the atmosphere. This may enable control of how quickly the artificial turf infill 202′ loses water when it is exposed to heat and sunlight. This may have the effect of prolonging the cooling effect.

FIG. 7 shows a further example of an artificial turf infill 202″ as illustrated by showing a further cross-sectional view of the natural fiber 500. The artificial turf fiber 500 displayed in FIG. 7 is similar to that in FIG. 6 except an additional further coating 700 has been coated over the subsequent coating 600 and the base coating 502. It can be seen that the number of openings 504 has again been greatly reduced. If a sufficient number of coatings are used then the artificial turf fiber 500 may be completely encapsulated in coatings. The further coating 700 may comprise at least one pigment and a binding agent where the binding agent comprises at least one type of polyurethane polymer. The further coating, the subsequent coating 600 and/or the base coating 502 in all of the examples shown in 5, 6 and 7 may also comprise various functional additives or components. For example there may be components which are used to provide flame retardants, provide infrared reflection or other properties.

Such an iterative processing of applying coatings can provide for an effective control of a number of openings and/or areas of the openings. In addition this iterative process can provide for a production of an integral coating of the artificial turf infill which has desired mechanical and/or structural properties and/or required wear and longevity.

FIG. 8 shows a flowchart which illustrates a method for manufacturing the artificial turf infill 202 illustrated in FIG. 5. First in step 800 a base composition is provided which comprises the natural fiber 500. The base composition further comprises a at least one first type of of pigment which may be a collection of multiple pigments and a fluid binding agent. The fluid binding agent comprises at least one type of polymer component. The natural fiber comprises any one of the following: hemp fiber, burlap fiber, sisal fiber, elephant grass, cotton, coconut fiber, and combinations thereof. Next in step 202 the method further comprises mixing the base composition. Then finally in step 804 the method further comprises adding water and a catalyst to the base composition during the mixing of the base composition to cure the fluid binding agent and the at least one first type of of pigment into a base coating 502 of the natural fiber 500.

FIG. 9 shows a flowchart which illustrates a method of manufacturing artificial turf infill 202′ shown in FIG. 6. The method of FIG. 9 includes the steps 800, 802, and 804 from FIG. 8. The method after performing step 804 further comprises providing a subsequent composition comprising the natural fiber 500 with the base coating 502. The subsequent composition further comprises a at least one second type of of pigment which may be the same or different than the at least one first type of of pigment and the fluid binding agent. The at least one second type of of pigment may also be a single pigment or formed from a collection of different pigments. Next in step 902 the method further comprises mixing the subsequent composition. Next the method further comprises the step 904 of adding water and the catalyst to the subsequent composition during the mixing of the subsequent composition to cure the fluid binding agent and the at least one second type of of pigment into a subsequent coating 600 of the natural fiber 500. The method then further comprises 906 providing the natural fiber with the subsequent coating as the artificial turf infill 202′.

FIG. 10 shows a flowchart which illustrates a method of manufacturing an artificial turf infill 202″ such as illustrated in FIG. 7. The method illustrated in FIG. 10 uses the artificial turf infill 202′ illustrated in FIG. 6. The method in FIG. 10 also includes the method steps of FIG. 9. After step 906 is performed the method further comprises providing 1000 a subsequent composition by adding at least one additive and the fluid binding agent to the natural fiber. The method then proceeds to step 1002 where the subsequent composition is mixed. Then finally in step 1004 water and catalyst are added to the subsequent composition during the mixing of the subsequent composition to cure the fluid binding agent and the at least one additive into a further coating 700 of the natural fiber. The method may end in step 1004 where the resulting artificial turf 202″ infill is provided. However, the addition of the subsequent coatings may be performed multiple times. The arrow going from step 1004 to 1000 indicates that this process may be repeated as many times as is desired. This step may be performed multiple times to add additional properties to the artificial turf infill such as greater coverage of openings 504 or even adding additional colors or functional coatings which may for instance be used to provide flame retardants, infrared reflective, antibacterial properties or even antifungal properties.

FIG. 11 illustrates some equipment which may be used for manufacturing the artificial turf infill 202, 202′, 202″ as depicted in FIGS. 5 through 7. The mixing vat can be used to perform any of the methods shown in FIGS. 8 through 10. FIG. 11 depicts a mixing vat 1100. The mixing vat has a rotatable shaft 1102 that is connected to a number of mixing paddles 1104. The mixing vat 1100 is filled with natural fibers 500. The natural fiber 500 can then be manufactured into artificial turf infill 202 by forming an base composition. The base composition comprises the the natural fiber 500, optionally at least one first type of pigment, and a fluid binding agent. The fluid binding agent, may for example, comprises at least one type of polymer component. Next in step the base composition is mixed. During this step, the mixing water and catalyst are added to the base composition to cure the fluid binding agent and the optional at least one type of pigment into an outer coating 502 that bonds to the surface of the natural fibers 500. Likewise, the artificial turf infills 202′ and 202″ as depicted in FIGS. 6 and 7 can be performed by using the methods depicted in FIGS. 9 and 10.

The apparatus depicted in FIG. 11 may be used for manufacturing the artificial turf infill as batches. It is also possible to manufacture the artificial turf infill as a continuous process using a flow reactor.

FIG. 12 illustrates an example of a flow reactor 1200. The example shown in FIG. 12 is illustrative and is not drawn to scale. The flow reactor 1200 comprises a rotatable shaft 1202 that is connected to a screw conveyor 1204. The screw conveyor 1204 is similar to an Archimedes screw, which is mounted horizontally. The flow reactor 1200 is shown as being filled with natural fiber 500. As the rotatable shaft 1202 is turned, it causes the natural fiber 500 to move through the flow reactor 1200. At an entrance there is an inlet 1208 for the natural fiber 500. This may be done on a continual basis as the shaft 1202 is rotated. This causes the natural fiber 500 to go to a first inlet 1210 for fluid binding agent and optionally at least one first type of pigment. At inlet 1210 the at least one at least one first type of of pigment and the fluid binding agent are added to the natural fiber 504 and become mixed with it as the shaft 1202 is rotated. When they are thoroughly mixed, the natural fiber 1204 and the rubber natural fiber 1206 and the at least one first type of pigment and the fluid binding agent form an base composition 1220. This base composition 1220 is then transported beneath a first inlet for water and catalyst 1212. The water and catalyst may be added on a continual or intermittent basis at this inlet 1212.

As the base composition 1220 is transported further along the flow reactor 1200 fluid binding agent and at least one pigment cure into the outer coating 502 such as depicted in FIG. 5. At this point, the artificial turf infill 202 has been formed.

In some examples the flow reactor may additional inlets so that additional layers or coatings can be applied. FIG. 7 also depicts optional inlets 1214 and 1216. After the outer coating 502 is formed, the base composition 1220 is transported underneath the second inlet 1214 for at least one pigment and fluid binding agent. At this point more of the pigment and fluid binding agent are added and the base composition 1220 becomes the subsequent composition 1222. The pigments used for the base composition and the subsequent composition may be identical or they may be different.

The subsequent composition 1222 is mixed and transported underneath the second inlet for water and catalyst 1216. The water and catalyst are then mixed with the subsequent composition 1222 and over time are further transported to the end of the flow reactor 1220. By the time the subsequent composition 1222 has reached the end of the flow reactor 1200 the subsequent coating 600 has formed on the natural fibers 500. At the very end, then the artificial turf infill 202′ exits the flow reactor 1200 at an outlet 1217. The the natural fiber 500 is then artificial turf infill 202′. The artificial turf infill 202′ is then shown as entering into an optional dryer 1218.

It is clear from FIG. 12 that the flow reactor may also be extended. For example if it is desired to put a third or fourth or even more coatings, the number of inlets in the flow reactor 1200 can simply be increased. This may involve moving the natural fiber at a different rotational rate or possibly even making the flow reactor 1200 longer.

LIST OF REFERENCE NUMERALS

-   -   100 artificial turf carpet     -   102 backing     -   104 artificial turf fiber tufts     -   106 row spacing     -   108 pile height     -   110 ground or floor     -   200 artificial turf     -   202 artificial turf infill     -   202′ artificial turf infill     -   202″ artificial turf infill     -   300 installing an artificial turf carpet     -   302 providing the artificial turf by spreading a layer of         artificial turf infill between the multiple artificial turf         fiber tufts     -   400 sprinkler     -   402 water     -   500 natural fiber     -   502 base coating     -   504 opening     -   600 subsequent coating     -   700 further coating     -   800 providing a base composition comprising a natural fiber, a         at least one first type of of pigment, and a fluid binding agent     -   802 mixing the base composition     -   804 adding water and a catalyst to the base composition during         the mixing of the base composition to cure the fluid binding         agent and the at least one first type of of pigment into a base         coating of the natural fiber     -   900 providing a subsequent composition comprising the natural         fiber with the base coating, a at least one second type of of         pigment, and the fluid binding agent     -   902 mixing the subsequent composition     -   904 adding water and the catalyst to the subsequent composition         during the mixing of the subsequent composition to cure the         fluid binding agent and the at least one second type of of         pigment into a subsequent coating of the natural fiber     -   906 providing the natural fiber with the subsequent coating as         artificial turf infill     -   1000 providing a subsequent composition by adding at least one         additive and the fluid binding agent to the natural fiber     -   1002 mixing the subsequent composition     -   1004 adding water and the catalyst to the subsequent composition         during the mixing of the subsequent composition to cure the         fluid binding agent and the at least one additive into a further         coating     -   1100 mixing vat     -   1102 rotatable shaft     -   1104 mixing paddles     -   1200 flow reactor     -   1202 rotatable shaft     -   1204 screw conveyor     -   1208 inlet for natural fiber     -   1210 first inlet for at least one pigment and fluid binding         agent     -   1212 first inlet for water and catalyst     -   1214 second inlet for at least one pigment and fluid binding         agent     -   1216 first inlet for water and catalyst     -   1217 outlet     -   1218 dryer     -   1220 base composition     -   1222 subsequent composition 

1. A method of manufacturing artificial turf infill (202, 202′, 202″), wherein the method comprises: providing (800) a base composition comprising a natural fiber (500), at least one first type of of pigment, and a fluid binding agent, wherein the fluid binding agent comprises at least one type of polymer component, wherein the natural fiber comprises any one of the following: hemp fiber, burlap fiber, sisal fiber, elephant grass, cotton, coconut fiber, and combinations thereof; mixing (802) the base composition; adding (804) water and a catalyst to the base composition during the mixing of the base composition to cure the fluid binding agent and the at least one first type of of pigment into a base coating (502) of the natural fiber.
 2. The method of manufacturing artificial turf infill of claim 1, wherein the natural fiber consists of any one of the following: hemp fiber, burlap fiber, sisal fiber, elephant grass, cotton, coconut fiber, and combinations thereof.
 3. The method of manufacturing artificial turf infill of claim 1, wherein the method further comprises: providing (900) a subsequent composition comprising the natural fiber with the base coating, a at least one second type of of pigment, and the fluid binding agent; mixing (902) the subsequent composition; adding (904) water and the catalyst to the subsequent composition during the mixing of the subsequent composition to cure the fluid binding agent and the at least one second type of of pigment into a subsequent coating of the natural fiber; an providing (906) the natural fiber with the subsequent coating as artificial turf infill (202′).
 4. The method of manufacturing artificial turf infill of claim 3, wherein any one of the following: the at least one first type of of pigment is identical with the at least one second type of of pigment, and the at least one first type of of pigment is a different color from the at least one second type of of pigment.
 5. The method of manufacturing artificial turf infill of claim 3 or 4, wherein the natural fiber with the base coating and the subsequent coating is re-coated at least one time by performing the following sequence: providing (1000) a subsequent composition (1222) by adding at least one additive and the fluid binding agent to the natural fiber; mixing (1002) the subsequent composition; and adding (1004) water and the catalyst to the subsequent composition during the mixing of the subsequent composition to cure the fluid binding agent and the at least one additive into a further coating, wherein the natural fiber with the further coating is provided as the artificial turf infill (202″).
 6. The method of manufacturing artificial turf infill of claim 5, wherein the at least one additive further comprises any one of the following: the at least one first type of pigment, the at least one second type of pigment, a flame retardant, aluminum trihydrate, magnesium hydroxide, an intumescent component, ammonium polyphosphate, exfoliated graphite, methylcellulose, zeolite, an antibacterial agent, silver, chitosan, an IR reflective pigment, a hindered amine light stabilizer, an anti-freeze additive, a de-icing additive, sodium chloride, potassium chloride, sodium formate, potassium formate, and combinations thereof.
 7. The method of manufacturing artificial turf infill of any one of the preceding claims, wherein the natural fiber comprises fibers less than 5 mm long, more preferably less than 1.5 mm long.
 8. The method of manufacturing artificial turf infill of any one of the preceding claims, wherein the at least one first type of pigment and/or the at least one second type of pigment comprises any one of the following: an inorganic pigment, an organic pigment, iron oxide, copper phthalo green complex, Chromium(III) oxide, a Copper Phthalocyanine pigment, a nickel azopigment, titanium oxide, and combinations thereof.
 9. The method of manufacturing artificial turf infill of any one of the preceding claims, wherein the polymer component comprises any one of the following: at least one type of monomer, at least one type of partially polymerized polymer, and combinations thereof.
 10. The method of manufacturing artificial turf infill of any one of the preceding claims, wherein the polymer component is cured into at least one type of polyurethane by the water and catalyst.
 11. The method of manufacturing artificial turf infill of any one of the preceding claims, wherein the fluid binding agent comprises a liquid polyurethane component.
 12. The method of manufacturing artificial turf infill of claim 11, wherein the liquid polyurethane component comprises an NCO terminal polymer, which may comprise a pre-polymer, a polymeric isocyanate, an oligomeric isocyanate, a monomer, and a mixture thereof.
 13. The method of manufacturing artificial turf infill of claim 11 or 12, wherein the liquid polyurethane component comprises an aromatic diisocyanate of the group of toluene diisocyanate and/or 2,2′-Methylene diphenyl diisocyanate and/or 2,4′-Methylene diphenyl diisocyanate and/or 4,4′-Methylene diphenyl diisocyanate.
 14. The method of manufacturing artificial turf infill of claim 11, 12, or 13, wherein the liquid polyurethane component comprises an aliphatic diisocyanate of the group hexamethylene diisocyanate, isophorone diisocyanate, and/or 1,4-cyclohexyldiisocyanate.
 15. The method of manufacturing artificial turf infill of any one of claims 11 through 14, wherein the liquid polyurethane component comprises an methylene diphenyldiisocyanate isomer mixture.
 16. The method of manufacturing artificial turf infill of any one of claims 11 through 15, wherein the liquid polyurethane component comprises a hydroxyl component, wherein the hydroxyl component is selected from the group of polyether polyol or polyester polyol.
 17. The method of manufacturing artificial turf infill of claim 16, wherein the hydroxyl component is based on a polyetherpolyol with a molecular weight between 500 and 10000, preferably the molecular weight is between 1500 and 6000, and more preferably the molecular weight is between 2000 and
 4000. 18. The method of manufacturing artificial turf infill of any one of the preceding claims, wherein the catalyst belongs to any one of the following groups: a secondary amine catalyst, a tertiary amine catalyst, and a metal organic catalyst.
 19. The method of manufacturing artificial turf infill of any claim 3 through 18 with reference to claim 3, wherein the method further comprises drying the subsequent composition before providing the natural fiber as the artificial turf infill.
 20. The method of manufacturing artificial turf infill of any one of the preceding claims, wherein the method is at least partially performed in a flow reactor.
 21. The method of manufacturing artificial turf infill of any one of claims 1 through 19, wherein the method is at least partially performed as a batch process.
 22. A method of manufacturing artificial turf (200), wherein the method further comprises: installing (300) an artificial turf carpet (100), wherein the artificial turf carpet comprises multiple artificial turf fiber tufts (104); and providing (302) the artificial turf by spreading a layer of artificial turf infill (202, 202′, 202″) between the multiple artificial turf fiber tufts, wherein the artificial turf infill comprises natural fiber (500), wherein the natural fiber comprises any one of the following: hemp fiber, burlap fiber, sisal fiber, elephant grass, cotton, coconut fiber, and combinations thereof, wherein the natural fiber comprises at least one outer coating (502, 600, 700), wherein the at least one outer coatings comprise at least one first type of pigment and a binding agent, wherein the binding agent comprises at least one type of polyurethane polymer.
 23. Artificial turf infill (202, 202′, 202″), wherein the artificial turf infill comprises natural fiber (500), wherein the natural fiber comprises any one of the following: hemp fiber, burlap fiber, sisal fiber, elephant grass, cotton, coconut fiber, and combinations thereof, wherein the natural fiber comprises at least one outer coating (502, 600, 700), wherein the at least one outer coating comprises at least one first type of pigment and a binding agent, wherein the binding agent comprises at least one type of polyurethane polymer.
 24. The artificial turf infill of claim 23, wherein the at least one outer coating comprises openings (504) that expose the natural fiber.
 25. An artificial turf, wherein the artificial turf comprises: an artificial turf carpet (100), wherein the artificial turf carpet comprises multiple artificial turf fiber tufts (104); and the artificial turf infill (202, 202′, 202″) according to claim 23 or
 24. 26. The artificial turf of claim 25, wherein the artificial turf further comprises a sprinkler system (400).
 27. The method of manufacturing artificial turf infill of any one of claims 1 through 21, wherein the base coating comprises first openings (504) that expose the natural fiber.
 28. The method of manufacturing artificial turf infill of any one of claims 27 and 3 through 21 with reference to claim 3, wherein the subsequent coating comprises second openings (504) that expose the natural fiber.
 29. The method of manufacturing artificial turf infill of claims 28 and 27, wherein a number of the first openings is bigger than a number of the second openings.
 30. The method of manufacturing artificial turf infill of any of claims 27 through 29, wherein a portion of the first openings is covered by the subsequent coating.
 31. The method of manufacturing artificial turf infill of any one of claims 5 through 21 and 27 through 30 with reference to claim 5, wherein the further coating comprises third openings (504) that expose the natural fiber.
 32. The method of manufacturing artificial turf infill of claims 31 and 29, wherein the number of the second openings is bigger than a number of the third openings.
 33. The method of manufacturing artificial turf infill of claims any one of claims 1 through 21 and 27 through 32 with reference to claims 27 and 3, wherein a portion of the first openings is covered by the subsequent coating.
 34. The method of manufacturing artificial turf infill of claims any one of claims 1 through 21 and 27 through 33 with reference to claims 28 and 5, wherein a portion of the second openings is covered by the further coating.
 35. The method of manufacturing artificial turf infill of claims 28 and 31, wherein a number of the second openings is bigger than a number of the third openings.
 36. The artificial turf infill of claim 23 or 24, wherein the at least one outer coating comprises openings (504) that expose the natural fiber. 